Advancing serologic diagnosis: assessing the efficacy of rErpY-like protein in human leptospirosis detection.

Leptospirosis is a globally distributed infectious disease caused by pathogenic spirochetes of the Leptospira genus, often overlooked. It is estimated that the disease affects approximately one million people annually, resulting in more than 58,900 deaths. The gold standard for serodiagnosis of leptospirosis is the Microscopic Agglutination Test (MAT). However, the limitations of this technique necessitate the exploration of alternative diagnostic methods. In this study, we evaluated the ErpY-like recombinant protein (rErpY-like) in the development of a serologic diagnostic assay for human leptospirosis. Eighty-six human sera samples, characterized by MAT, underwent evaluation through indirect IgM-ELISA and IgG-ELISA. The sensitivity and specificity values obtained from IgM-ELISA were 60% and 76%, respectively, while those from IgG-ELISA were 96.4% and 100%, respectively. The use of the rErpY-like protein in both IgM-ELISA and IgG-ELISA proves to be a sensitive and specific method for antibody detection. This could potentially serve as a valuable alternative tool in the diagnosis of human leptospirosis.

Disability-adjusted life years due to leptospirosis in Monaragala District of Sri Lanka.

Leptospirosis is a zoonotic infection with significant morbidity and mortality. As an occupational disease, it has become a global concern due to its disease burden in endemic countries and rural areas. The aim of this study was to assess disease burden in terms of Disability-adjusted life years (DALYs) of leptospirosis.A hospital-based descriptive cross-sectional study was conducted using 450 clinically diagnosed leptospirosis patients admitted to base and above hospitals in Monaragala District, Sri Lanka, using a pre-tested interviewer-administered questionnaire. The patients were followed up until normal day-to-day life after discharge. Estimation of DALYs was done using laboratory-confirmed leptospirosis patients. Leptospirosis disease burden in Monaragala District was 44.9 DALYs per 100,000 population, which includes 33.18 Years of life losts and 10.9 YLDs. The incidence of leptospirosis in Monaragala District during the study period was 59.8 per 100,000 population, and the case fatality rate (CFR) was 1.5% and 75% of deaths were among males.The disease burden of leptospirosis in Monaragala District was significantly high and urgent efforts to control and prevent leptospirosis should be a priority.

Leptospiral Uveitis: Case Series and Review of Literature.

AIM: To present the clinical features and review of literature of leptospiral uveitis. METHODS: We present clinical features of patients with leptospiral uveitis with positive Leptospira IgM antibodies. RESULTS: Twenty-six eyes of 24 patients, 11 males (45.8%), were included. The mean age was 37.5 ± 15.6 years. 91.7% had unilateral uveitis, 88.5% panuveitis, 11.5% anterior uveitis, 15.4% had hypopyon, 8% had cataract and 3.8% eyes had cystoid macular edema. Vitritis with characteristic vitreous membranes was an important feature. Retinal and choroidal vasculature were preserved on swept-source optical coherence tomography angiography. Mean presenting BCVA was logMAR0.49 ± 0.41, while final BCVA was logMAR0.04 ± 0.13. The mean duration for complete resolution of uveitis was 39.1 ± 15.5 days. 84.6% eyes achieved BCVA 6/6. CONCLUSION: Leptospiral uveitis is an under-reported entity. It may present as anterior uveitis or panuveitis. It must be included in the differential diagnosis of non-granulomatous uveitis. The visual prognosis is usually favorable even in severe cases.

Clinical manifestations of human leptospirosis: bacteria matter.

Introduction: A high incidence of human leptospirosis is recorded on Mayotte, an oceanic island located in southwestern Indian Ocean, but the severity of the disease appears relatively mild in terms of mortality rate and admission to the intensive care unit. It has been proposed that mild leptospirosis may result from a limited virulence of some of the occurring Leptospira species to which the population is exposed. Methods: Clinical and biological data of patients admitted to the Centre Hospitalier de Mayotte were collected and the infecting Leptospira species were determined through molecular typing. Results: Leptospira interrogans was detected in the minority of admitted patients but most of these patients suffered from severe forms, with 50% admitted to intensive care unit and suffering from organ failures. Nineteen percent of patients infected with Leptospira borgpetersenii were admitted to the intensive care, with 13% displaying organ failures, and one patient died. Leptospira mayottensis was found in 28% of the patients and not a single severe case was observed. Discussion: The distribution of Leptospira species in patients was not different from that reported 10-15 years ago and bacterial genotypes were very closely related to those previously reported. These results highlight the importance of the diversity of pathogenic Leptospira circulating on Mayotte island and are in keeping with distinct outcome of the disease depending on the infecting Leptospira. Altogether, presented data support that the infecting Leptospira species is an important driver of disease severity in humans.

Incidence and distribution of human leptospirosis in the Western Cape Province, South Africa (2010-2019): a retrospective study.

Introduction: leptospirosis is an emerging zoonosis of global importance. In South Africa, the infection is an underreported public health concern, with limited information on its incidence and distribution. This study investigated the incidence of human leptospirosis in Western Cape Province (WCP) between 2010 and 2019, and compared the incidence based on seasonal and demographic factors. Methods: a retrospective study was conducted with data on leptospirosis diagnoses in WCP obtained from the National Health Laboratory Services. With the provincial population sizes as the denominator, incidence of leptospirosis was estimated and expressed as cases per 100,000 population. Negative binomial regression was used to estimate the effect of sex, season, and year on the incidence of leptospirosis. Results: two hundred and fifty-four (254) cases of leptospirosis were reported between 2010 and 2019, with the highest number of cases being in 2015 and the annual incidence ranged between 0.15 and 0.66/100,000 population. Males had a higher incidence compared to females (0.55 vs. 0.25/ 100,000 population; incidence rate ratio (IRR) 2.2, 95% CI: 1.66,3.03). The 18-44 age cohort had the highest average incidence (0.56/100,000 population), while the ≤17 age cohort had the lowest incidence (0.07/100,000 population). The 18-44 (IRR 8.0, 95% CI: 4.65,15.15) and ≥45 (IRR 7.4, 95% CI: 4.17,14.17) age cohorts were more at risk of infection compared to ≤17 age cohort. Conclusion: leptospirosis is an important zoonosis in WCP disproportionately affecting males and the productive age demographic groups. These findings should enhance targeted prevention and provoke further investigation on the importance of environmental and socioeconomic factors on leptospirosis burden.

Evaluating immunochromatographic test kits for diagnosis of acute human leptospirosis: A systematic review.

Background: Leptospirosis, a common zoonotic infection in developing countries, usually progresses to severe conditions and poor outcomes when not detected early. Microscopic agglutination test (MAT) and culture are available but are not accessible in all areas and are usually confined to specialized laboratories. There are several available immunochromatographic test kits (ICT) that offer ease of use, access, and affordability, but diagnostic accuracy is not yet well established. In this paper, we aim to review published literature on the use of ICTs for the detection of leptospirosis and evaluate their diagnostic efficiency. Materials and methods: We systematically searched multiple databases (PubMed, Cochrane Library, and Google Scholar), including gray literature sources for published research articles as of April 13, 2022, on the diagnosis of acute leptospirosis using ICT. We assessed the methodological quality of each article using the revised QUADAS-2. Results: From a total of 41 articles, 30 (73.2%) were identified as potentially relevant after reviewing the title and abstract and eliminating duplicate articles; then, 22 (53.7%) articles were included after scrutinizing and applying the inclusion/exclusion criteria to the full text. Almost all test kits detect IgM antibodies against the Leptospira species except for one which used IgG as a marker for diagnosis of acute leptospirosis. A wide range of sensitivity (15.8%-100.0%) and specificity (37.3%-100.0%) were recorded. Lipopolysaccharide (LPS)-specific Immunochromatographic Lateral Flow Assay presented the highest sensitivity (∼93-100%) and specificity (∼99.19-100%). Conclusion: Rapid diagnosis of acute leptospirosis is highly warranted; however, available test kits present a wide range of diagnostic accuracy. We found that LPS-specific ICT kit has the highest diagnostic efficiency; however, our analysis was limited by the included studies' heterogeneity in design and reporting; thus, we recommend standardization in the conduct and reporting of diagnostic accuracy of test kits as it is vital to evaluate the reliability of the test kit.

Comparative proteomic analysis of Leptospira interrogans serogroup Icterohaemorrhagiae human vaccine strain and epidemic isolate from China.

Leptospira interrogans serogroup Icterohaemorrhagiae is the predominant pathogen causing leptospirosis in China and is still used as the vaccine strain for the current human inactivated vaccine. Unlike the clade ST17, which is distributed worldwide, ST1 is the most prevalent in serogroup Icterohaemorrhagiae in China. To further characterize leptospiral pathogens, isobaric tags for relative and absolute quantitation and parallel reaction monitoring were used to analyze differences at the proteomic level between serogroup Icterohaemorrhagiae vaccine strain 56001 (ST1) and circulating isolate 200502 (ST17) from different periods. Two hundred and eighty-one proteins were differentially expressed between the circulating isolate and vaccine strain, of which 166 were upregulated (> 1.2-fold change, P < 0.05) and 115 (< 0.8-fold change, P < 0.05) were downregulated. Function prediction revealed that nine upregulated proteins were outer membrane proteins, including several known immunogenic and/or virulence-related proteins, such as ompL1, LipL71, and LipL41. Furthermore, important expression differences in carbohydrate, amino acid, and energy metabolism and transport proteins were identified between both strains from different clusters, suggesting that these differences may reflect metabolic diversity and the potential of the pathogens to adapt to different environments. In summary, our findings provide insights into a better understanding of the component strains of the Chinese human leptospirosis vaccine at the proteomic level. Additionally, these data facilitate evaluating the mechanisms by which pathogenic Leptospira species adapt to the host environment.

Effects of rainfall on human leptospirosis in Thailand: evidence of multi-province study using distributed lag non-linear model.

Leptospirosis is a zoonotic bacterial disease that remains an important public health problem, especially in tropical developing countries. Many previous studies in Thailand have revealed the outbreak of human leptospirosis after heavy rainfall, but research determining its quantitative risks associated with rainfall, especially at the national level, remains limited. This study aims to examine the association between rainfall and human leptospirosis across 60 provinces of Thailand. A quasi-Poisson regression framework combined with the distributed lag non-linear model was used to estimate province-specific association between rainfall and human leptospirosis, adjusting for potential confounders. Province-specific estimates were then pooled to derive regional and national estimates using random-effect meta-analysis. The highest risk of leptospirosis associated with rainfall at national level was observed at the same month (lag 0). Using 0 cm/month of rainfall as a reference, the relative risks of leptospirosis associated with heavy (90th percentile), very heavy (95th percentile), and extremely heavy (99th percentile) rainfall at the national level were 1.0994 (95% CI 0.9747, 1.2401), 1.1428 (95% CI 1.0154, 1.2862), and 1.1848 (95% CI 1.0494, 1.3378), respectively. The highest risk of human leptospirosis associated with rainfall was observed in the northern and north-eastern regions. Specifically, the relative risks of leptospirosis associated with extremely heavy rainfall in northern and north-eastern regions were 1.2362 (95% CI 0.9110, 1.6775) and 1.2046 (95% CI 0.9728, 1.4918), respectively. Increasing rainfall was associated with increased risks of leptospirosis, especially in the northern and northeastern regions of Thailand. This finding could be used for precautionary warnings against heavy rainfall. Supplementary Information: The online version contains supplementary material available at 10.1007/s00477-022-02250-x.

A case-control study of agricultural and behavioral factors associated with leptospirosis in Vietnam.

INTRODUCTION: Leptospirosis is a neglected disease in Vietnam. Until now, there has been limited knowledge about risk factors of this disease in Vietnam. The study was carried out to identify agricultural and behavioral factors associated with the transmission of leptospirosis in Vietnam. METHODS: This matched retrospective hospital-community-based case-control study was conducted from 1 October 2018 to 31 October 2019. We recruited cases from 11 selected government hospitals in three provinces of Vietnam, while controls were selected from the same communes of cases and matched by age (± 2 years) and sex. Microscopic agglutination test (MAT) and enzyme-linked immunosorbent assay (ELISA) were applied to determine confirmed cases, while only MAT was used to identify controls with a single high MAT titer < 1:100. RESULTS: 504 participants (252 cases and 252 controls) were identified. Cultivating (OR 2.83, CI 1.38-5.79), animal farming (OR 8.26, CI 2.24-30.52), pig owners (OR 10.48, CI 5.05-21.73), cat owners (OR 2.62, CI 1.49-4.61) and drinking unboiled water (OR 1.72, CI 1.14 -2.59, p = 0.010) were significantly associated with human leptospirosis in Vietnam. Hand washing after farming/ gardening (OR 0.57, CI 0.38-0.86, p = 0.007) and bathing after farming, gardening, contact with cattle and poultry (OR 0.33, CI 0.19-0.58, p = 0.000) were determined as protective factors for this disease. CONCLUSIONS: In short, the case-control study has revealed the risks in agricultural and animal practices and protective behavioral factors related to human leptospirosis in Vietnam. The findings suggested promotion of communication and health education programs targeting health behaviors in daily life and agricultural practices. Using personal protective equipment such as gowns, gloves, and boots during agricultural practices, especially cultivating and animal farming, is most recommended.

Characteristics of human leptospirosis in three different geographical and climatic zones of Vietnam: a hospital-based study.

BACKGROUND: To our knowledge, this study is the first report on the seroprevalence of human leptospirosis and its epidemiological profile in 3 different geographical and climatic zones of Vietnam. METHODOLOGY: A hospital-based surveillance in 11 public hospitals in 3 provinces in Vietnam enrolled 3,815 patients with suspected leptospirosis. Two consecutive enzyme-linked immunosorbent assay IgM and a single microscopic aggregation test were applied at a 1:100 to 1:800 dilution for probable or confirmed cases. RESULTS: The findings showed that of the 3,815 suspected cases, 68 (1.8%) were Leptospira-confirmed and 248 (6.5%) probable cases, whereas more than a third were positive for acute ELISA-IgM sera. Furthermore, 20 different serovars were found, of which Wolffi (14.2%), Hebdomadis (13.8%), and Icterohaemorrhagiae (12.6%) were the most predominant. The ratio of probable and confirmed cases of leptospirosis between females and males was 1.4:1, and their clinical manifestation was not specific. Cases were more likely to be detected in groups that are farmers, pet raising or livestock farming, of working age, practicing either wading in mud or walking barefoot, or exposed to heavy rainfall. CONCLUSIONS: Analysis of human leptospirosis has indicated fairly high seroprevalence and diversity of Leptospira serovars circulating in all studied geographical zones in Vietnam. The findings suggest an imperative need for effective measures of disease prevention, especially in high-risk groups.

Efectividad de la reacción en cadena de la polimerasa en tiempo real (PCR-RT) e Inmunodot en el diagnóstico temprano de leptospirosis: análisis comparativo con la prueba de Microaglutinación (MAT) / Effectiveness of the real-time polymerase chain reaction (RT-PCR) and Immunodot in the early diagnosis of Leptospirosis: comparative analysis with the Microagglutination test (MAT)

Introducción: la leptospirosis es una enfermedad infecciosa producida por espiroquetas del género Leptospira. Se disemina a través de la orina de animales domésticos, con mayor frecuencia por roedores. En República Dominicana se necesitan pruebas confiables para el diagnóstico en etapas tempranas de la enfermedad. En el presente trabajo se aborda la validez diagnóstica del PCR en Tiempo Real y del IGM (INMUNODOT) en comparación con la prueba de Microaglutinación (MAT). Materiales y métodos: se realizó un estudio observacional, descriptivo, de corte transversal con 69 pacientes admitidos en el Hospital Regional "José María Cabral y Báez" con diagnóstico presuntivo de leptospirosis desde el 2010 hasta el 2012. Resultados: del total de los casos (69), la mayoría fueron del sexo masculino (94.2 %), menores de 49 años (79.4 %) y provenían de la provincia de Santiago (58 %). La mortalidad fue de 52.1 % de los cuales 52.3 % fueron reportados positivos para Leptospira y 47.6 % resultaron negativos según el MAT. Al comparar los resultados de PCR en relación al MAT se obtuvo una sensibilidad de 27.3 % y una especificidad de 80 %. Los resultados del PCR y del Immunodot fueron equivalentes. Conclusión: en el presente trabajo la realización del PCR en sangre, después del 5to día de inicio de la enfermedad, no demostró ser mejor que la Inmunodot para la detección temprana de la enfermedad, al contrastarlos con el resultado del MAT. En República Dominicana, los casos hospitalizados con diagnóstico presuntivo de leptospirosis permanecen con muy alta mortalidad. Por tanto, es prioritario optimizar el diagnóstico y el tratamiento de estos casos. En este estudio, los casos confirmados con Leptospirosis que fallecieron indican que debe actualizarse el protocolo de tratamiento y asegurarse que pueda implementarse. Por otra parte, los casos no confirmados fallecidos exigen investigar otras causas de enfermedad como la Infección por Hanta Virus.

Introduction: Leptospirosis is an infectious disease caused by spirochaetes of the genus Leptospira. It spread through the urine of domestic animals most frequently in rodents. Need reliable tests to diagnose in early stages of the disease and it has been proposed the use of the PCR in real-time as an option. The present work deals with the diagnostic real-time PCR and IGM (INMUNODOT) in comparison with the Microagglutination (MAT) test. Materials and methods: An observational, descriptive, cross-sectional study with 69 patients admitted as possible Leptospirosis in the Hospital "Jose Maria Cabral y Báez" of Santiago from 2010 to 2012. Results: Of the total cases (69), most were male (94.2%), under 49 years of age (79.4%) coming from the province of Santiago (58%). Mortality was 52.1% of which 52.3% were reported positive for leptospirosis and 47.6% were negative according to the MAT. To compare the results of PCR in relation to the MAT was obtained a sensitivity of 27.3% and a specificity of 80%. The results of the PCR and immunodot were equivalent. Conclusion: In this study, the realization of the PCR in blood after the 5th day of the disease not proved to be better than the Inmunodot for the early detection of the disease. Is necessary to evaluate cases less than 5th day. In the Dominican Republic, hospitalized with a presumptive diagnosis of Leptospirosis cases remain with very high mortality. Therefore, it is important to optimize the diagnosis and treatment of these cases. In this study, confirmed cases with Leptospirosis who died, indicate that you must upgrade the treatment protocol and ensure that it can be implemented. On the other hand, the deceased not confirmed cases require to investigate other causes of disease as the Hanta Virus infection.

Revisiting the development of vaccines against pathogenic leptospira: innovative approaches, present challenges, and future perspectives

Human vaccination against leptospirosis has been relatively unsuccessful in clinical applications despite an expressive amount of vaccine candidates has been tested over years of research. Pathogenic Leptospira encompass a great number of serovars, most of which do not cross-react, and there has been a lack of genetic tools for many years. These obstacles have hampered the understanding of the bacteria’s biology and, consequently, the identification of an effective antigen. Thus far, many approaches have been used in an attempt to find a cost-effective and broad-spectrum protective antigen(s) against the disease. In this extensive review, we discuss several strategies that have been used to develop an effective vaccine against leptospirosis, starting with Leptospira-inactivated bacterin, proteins identified in the genome sequences of pathogenic Leptospira, including reverse vaccinology, plasmid DNA, live vaccines, chimeric multi-epitope, and toll- and nod-like receptors agonists. This overview should be able to guide scientists working in the field to select potential antigens and to choose the appropriate formulation to administer the candidates.

Regional Prevalence of Intermediate Leptospira spp. in Humans: A Meta-Analysis.

Leptospirosis is one of the most widespread bacterial diseases caused by pathogenic Leptospira. There are broad clinical manifestations due to varied pathogenicity of Leptospira spp., which can be classified into three clusters such as pathogenic, intermediate, and saprophytic. Intermediate Leptospira spp. can either be pathogenic or non-pathogenic and they have been reported to cause mild to severe forms of leptospirosis in several studies, contributing to the disease burden. Hence, this study aimed to estimate the global prevalence of intermediate Leptospira spp. in humans using meta-analysis with region-wise stratification. The articles were searched from three databases which include PubMed, Scopus, and ScienceDirect. Seven studies were included consisting of two regions based on United Nations geo-scheme regions, among 469 records identified. Statistical analysis was performed using RevMan software. The overall prevalence estimate of intermediate Leptospira spp. in humans was 86% and the pooled prevalences were 96% and 17% for the American and Asia regions, respectively. The data also revealed that Leptospira wolffii was the most predominantly found compared to the other intermediate species identified from the included studies, which were Leptospira inadai and Leptospira broomii. The estimated prevalence data from this study could be used to develop better control and intervention strategies in combating human leptospirosis.

Cardiac tamponade secondary to leptospirosis. A rare association: A case report.

Herein is described the case of a 39-year-old female agronomist who was admitted to hospital after a syncopal episode. She had had fever, abdominal pain, nausea, and vomiting for the previous month. The patient showed signs of hypoperfusion, so a trans-thoracic echocardiography was done, demonstrating the presence of a cardiac tamponade. An emergency pericardiocentesis was performed, draining 500 ml of hematic content. Thoracic-abdominal computed tomography showed bilateral pleural effusion and also peritoneal effusion. Laboratory tests were compatible with an inflammatory situation with neutrophilic leukocytosis, alteration of hepatic function, and a plateau elevation of high-sensitivity troponin T. Colchicine was initiated but the evolution of the patient was torpid, making necessary the performance of a pericardial window due to an abrupt increase of pericardial effusion and echocardiographic signs of impending cardiac tamponade. Two chest tubes were inserted due to an increasing bilateral pleural effusion. Serology was positive for Leptospira spp. so doxycycline was initiated. She reported that she had inspected a rice-field the previous month. The patient presented a good response to the treatment, being discharged from hospital completely asymptomatic, with no pericardial effusion and practically resolved pleural effusions. She was evaluated again one month later, with no trace of effusions or symptoms. .

Revisiting the Development of Vaccines Against Pathogenic Leptospira: Innovative Approaches, Present Challenges, and Future Perspectives.

Human vaccination against leptospirosis has been relatively unsuccessful in clinical applications despite an expressive amount of vaccine candidates has been tested over years of research. Pathogenic Leptospira encompass a great number of serovars, most of which do not cross-react, and there has been a lack of genetic tools for many years. These obstacles have hampered the understanding of the bacteria's biology and, consequently, the identification of an effective antigen. Thus far, many approaches have been used in an attempt to find a cost-effective and broad-spectrum protective antigen(s) against the disease. In this extensive review, we discuss several strategies that have been used to develop an effective vaccine against leptospirosis, starting with Leptospira-inactivated bacterin, proteins identified in the genome sequences of pathogenic Leptospira, including reverse vaccinology, plasmid DNA, live vaccines, chimeric multi-epitope, and toll- and nod-like receptors agonists. This overview should be able to guide scientists working in the field to select potential antigens and to choose the appropriate formulation to administer the candidates.

Human leptospirosis in the Marche region: Over 10 years of surveillance.

We conducted a 10 years' retrospective study in 347 symptomatic individuals to assess the regional distribution of leptospirosis. A total of 173 individuals were diagnosed positive (49.8%): 11.5% were found positive to Leptospira by microscopic agglutination test positive, whereas 38.3% were found positive by microscopy analysis. The maximum peak of leptospirosis was reached in 2017 (n = 32). The most common serovars were Icterohaemorrhagiae and Poi.

Microscopio agglutination test: Variables that affect the time of serological confirmation of human leptospirosis cases / Test de microaglutinación: variables que afectan el tiempo de confirmación de los casos humanos de leptospirosis

Abstrac Leptospirosis is considered an endemic disease in Buenos Aires province, Argentina,with human cases reported annually from rural and urban areas. The aim of the study was todescribe the variables that influence the delay in the serological confirmation of leptospirosisin human cases (period 2006-2014) from Buenos Aires province. Sixty-four percent (64%) ofcases could be confirmed by microscopic agglutination test (MAT) with the first sample. The time of confirmation of the human leptospirosis cases was on average 21 days from the onset of the first clinical signs, and varied depending on the distance of the different sanitary regions. The geographical distribution of the confirmed leptospirosis human cases, in addition to the high number of suspected cases and probable cases (which could not be confirmed by MAT), demonstrate that leptospirosis is endemic and underreported in Buenos Aires province, and that distance and lack of resources could be determinant factors of this situation.

Resumen La leptospirosis se considera una enfermedad endémica en la provincia de Buenos Aires, con casos humanos registrados anualmente en áreas rurales y urbanas. El objetivo de este estudio fue describir las variables que influyen en el retraso de la confirmación serológica de la leptospirosis en humanos, a partir del análisis de los casos ocurridos en el período 2006-2014 en la provincia de Buenos Aires. El 64% de los casos fue confirmado por microaglutinación (MAT) con la primera muestra clínica. El tiempo de confirmación promedio fue de 21 días desde el inicio de los primeros signos clínicos; este valor se vio afectado por la distancia entre los centros de salud y los laboratorios de referencia en las distintas regiones sanitarias. La distribución geográfica de los casos confirmados de leptospirosis en humanos, además del alto número de casos sospechosos y probables (que no pudieron ser confirmados por MAT), demuestra que esta afección es endémica y se encuentra subregistrada en la provincia de Buenos Aires, y que la distancia y la falta de recursos serían factores determinantes de estas características.

Comparative genomic analysis of Chinese human leptospirosis vaccine strain and circulating isolate.

LEPTOSPIRA INTERROGANS: serogroup Canicola is one of the most important pathogens causing leptospirosis and is used as a vaccine strain of the current Chinese human leptospirosis vaccine. To characterize leptospiral pathogens, L. interrogans serogroup Canicola vaccine strain 611 and circulating isolate LJ178 from different hosts at different periods were sequenced using a combined strategy of Illumina X10 and PacBio technologies, and a comprehensive comparative analysis with other published Leptospira strains was conducted in this study. High levels of genomic similarities were observed between vaccine strain 611 and circulating isolate LJ178; both had two circular chromosomes and two circular extrachromosomal replicons. Compared with the strain 611 genome, 132 single nucleotide polymorphisms and 92 indels were found in strain LJ178. The larger lipopolysaccharide biosynthesis locus of serogroup Canicola was identified in both genomes. The phylogenetic analysis based on whole-genome sequences revealed that serogroup Canicola was not restricted to a specific host or geographic location, suggesting adaptive evolution associated with the ecologic diversity. In summary, our findings provide insights into a better molecular understanding of the component strains of human leptospirosis vaccine in China. Furthermore, these data detail the genetic composition and evolutionary relatedness of Leptospira strains that pose a health risk to humans.

Microscopic agglutination test: Variables that affect the time of serological confirmation of human leptospirosis cases.

Leptospirosis is considered an endemic disease in Buenos Aires province, Argentina, with human cases reported annually from rural and urban areas. The aim of the study was to describe the variables that influence the delay in the serological confirmation of leptospirosis in human cases (period 2006-2014) from Buenos Aires province. Sixty-four percent (64%) of cases could be confirmed by microscopic agglutination test (MAT) with the first sample. The time of confirmation of the human leptospirosis cases was on average 21 days from the onset of the first clinical signs, and varied depending on the distance of the different sanitary regions. The geographical distribution of the confirmed leptospirosis human cases, in addition to the high number of suspected cases and probable cases (which could not be confirmed by MAT), demonstrate that leptospirosis is endemic and underreported in Buenos Aires province, and that distance and lack of resources could be determinant factors of this situation.

Seroprevalencia de leptospirosis en grupos humanos en riesgo por factores ambientales, laborales o sociales / Seroprevalence of leptospirosis in human groups at risk due to environmental, labor or social conditions

Abstract Leptospirosis is important in Uruguay due to the economic loss caused by the diseases of production animals, mainly bovines, and also due to frequent human infection. We decided to study anti-Leptospira antibodies in the sera of dairy workers, rice laborers, veterinarians, suburban slum dwellers and garbage recyclers. Our aims were to estimate the seroprevalence of infection by Leptospira spp. in these people at risk, the relative importance of the known risk factors associated with infection, and the impact of human infections in each setting. Groups at risk were identified and 35 visits to their locations were made, conducting field surveys and exchange talks for information and education. Simple epidemiological questionnaires were administered and sera samples were taken from 308 persons. The microagglutination Technique (MAT) and the IgM Indirect Immunofluorescence (IIF) assay were employed to detect antibodies. Environmental water samples, canine and equine sera were also examined. More than 45% of human sera were reactive and the studied groups were confirmed to be widely exposed to infection. Female sera were frequently reactive, though most illnesses occur in men, and the most severe cases in elderly males; the emergence and evolution of the disease may strongly depend on the host condition and functions. Animal contact and unsafe water usage were the main identified risk factors to be considered in prevention. Fifty per cent of the studied horses showed a positive MAT reaction. The underdiagnosis of the illness and its long-term symptoms require further study, as well as greater health and social attention efforts.

Resumen La leptospirosis es importante en Uruguay por las pérdidas económicas que ocasionan las enfermedades en los animales de producción, principalmente en los bovinos, y a causa de la frecuente infección humana. Decidimos estudiar anticuerpos anti -Leptospira en trabajadores de tambo y de plantaciones de arroz, así como en veterinarios, habitantes de asentamientos y recicladores de residuos. Buscamos evaluar la importancia de distintos factores de riesgo conocidos asociados con la infección por Leptospira spp., y estimar la frecuencia y el impacto de las infecciones humanas en la población expuesta. Se efectuaron 35 visitas a colectivos de riesgo, realizando relevamientos de campo e intercambios educativos, llenando formularios epidemiológicos sencillos y tomando muestras de sangre a 308 personas. Se investigaron anticuerpos séricos con técnicas de microaglutinación (MAT) e inmunofluorescencia indirecta para IgM. Se examinaron también, muestras de agua ambiental, y sueros caninos y equinos. Más del 45% de los sueros humanos fueron reactivos y se confirmó que los grupos estudiados estaban ampliamente expuestos a la infección. Los sueros de mujeres fueron frecuentemente reactivos, aunque la mayoría de las enfermedades ocurren en varones, y los casos más graves en varones añosos. La emergencia y la evolución de la afección pueden depender fuertemente del estado del huésped y su respuesta. El contacto con animales y el uso de agua insegura fueron los principales factores de riesgo identificados para considerar en la prevención. El 50% de los sueros equinos fueron reactivos por MAT. Es necesario incrementar los esfuerzos de atención social y sanitaria en estos sectores, superar el subdiagnóstico y estudiar la evolución y la sintomatología a largo plazo de los pacientes.